Laser anemometer measurements in a compressor rotor flowfield at off-design conditions

Popovski, P.; Lakshminarayana, B.

doi:10.2514/3.9440

Cited by 8 publications

(8 citation statements)

References 7 publications

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“…The errors introduced by the measuring probes can be very serious inside the radial turbine guide vanes because of the small flow passages, and their correction is very difficult due to the high velocity gradients in the proximity of the walls. The nonintrusive, LDV and other laser velocimetry measuring techniques avoid these difficulties and have been successfully used to obtain flow measurements in various turbomachine configurations including fans, centrifugal impellers, stators and rotors of axial compressors and turbines [24][25][26][27][28][29][30][31]. This paper presents the results of an experimental study conducted to obtain 3-D flow measurements through the guide vanes of a radial inflow turbine using a three-component LDV system.…”

Section: Introductionmentioning

confidence: 99%

LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

Eroğlu

Tabakoff

1989

Volume 1: Turbomachinery

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The results of LDV measurements and investigation of the detailed flow field in a radial inflow turbine nozzle are presented. The flow velocities were measured at upstream, inside and downstream of the nozzle blades for two different mass flow rates, using a three-component LDV system. Results are presented as flow turbine cascades because of the radial pressure gradients and the incidence effects. Although they show the existance of the leading edge vortices, the of passage vortices are either too weak or they do not at exist. The shape of leading edge vortices depends strongly on the incidence angle.

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Section: Introductionmentioning

confidence: 99%

LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

Eroğlu

Tabakoff

1989

Volume 1: Turbomachinery

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“…Both the size of this vortex and the magnitude of the streamwise velocities in this secondary flow region are well predicted. The secondary velocities are shown in averaging technique [Popovski and Lakshminarayana (1986)]. The pressure probe data is available for this rotor.…”

Section: Computational Considerationsmentioning

confidence: 99%

“…At convergence, the parabolic stability constraint was more restrictive than the hyperbolic constraint, that is At., < At,, for 6.5 % of the grid points in the domain. In Figure 7, the blade to blade axial velocity distributions, obtained at several spanwise locations by Popovski and Lakshminarayana (1986), using LDV measurements, is presented with the Navier-Stokes predictions. The rotational inviscid flow features are seen to be well captured by the simulation, including immediately upstream of the leading edge where the presence of the blade gives rise to small velocity magnitudes due to the proximity of the stagnation point (inviscid effect).…”

Section: =300°mentioning

confidence: 99%

“…wall wall Measured inlet axial and tangential velocities, provided in Popovski and Lakshminarayana (1986), were interpolated onto the inlet plane to pr o\ ide the rotor flow inlet boundary conditions discussed previously. Vr/Vb= 0 .4 .0 .4 .0 .4 .0 .4 .0 .4 A composite law-of-the-wall due to Spalding [see White (1974) for instance] was used to approximate the total velocities between the endwalls and the first measurement location away from these walls.…”

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confidence: 99%

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Three-Dimensional Navier-Stokes Computation of Turbomachinery Flows Using an Explicit Numerical Procedure and a Coupled k-ε Turbulence Model

Kunz

Lakshminarayana

1991

Volume 1: Turbomachinery

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An explicit, three-dimensional, coupled Navier-Stokes/k-ε technique has been developed and successfully applied to complex internal flow calculations. Several features of the procedure, which enable convergent and accurate calculation of high Reynolds number two-dimensional cascade flows have been extended to three-dimensions, including a low Reynolds number compressible form of the k-ε turbulence model, local timestep specification based on hyperbolic and parabolic stability requirements, and eigenvalue and local velocity scaling of artificial dissipation operators. A flux evaluation procedure which eliminates the finite difference metric singularity, at leading and trailing edges, on H- and C-grids, is presented. The code is used to predict the pressure distribution, primary velocity and secondary flows in an incompressible, turbulent curved duct flow for which CFD validation quality data is available. Also, a subsonic compressor rotor passage, for which detailed laser, rotating hot-wire and five-hole pressure probe measurements have been made is computed. Detailed comparisons between predicted and measured core flow and near wall velocity profiles, wake profiles, and spanwise mixing effects downstream of the rotor passage are presented for this case. It is found that the technique provides accurate and convergent engineering simulation of these complex turbulent flows.

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“…18 Hub corner stall, responsible for high loss region, was also observed by Schulz and Gallus 19 at the exit of an isolated subsonic compressor stator at off-design operating points. An extensive range of operating points from design to stall was also studied by Popovski and Lakshminarayana, 20 and Schreeve et al, 21 respectively, in a compressor rotor and a compressor cascade.…”

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confidence: 95%

Unsteady Off-Design Velocity and Reynolds Stresses in an Axial Compressor

Michon

Miton

Ouayhaya

2005

Journal of Propulsion and Power

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The aim of the present work is to provide unsteady experimental data about the flow in a one-stage axial compressor. Some particular flow features are described and discussed. The operating conditions considered here concern an off-design point that is close to the compressor rotating stall limit. Measurements were performed with a three-dimensional laser Doppler velocimeter. Twenty-eight axial sections were surveyed from the rotor inlet to the stator outlet. In each section, velocity and velocity fluctuation measurements concerned more than 250 points. Thus, more than 8000 locations of measurement were investigated in the rotating and in the fixed parts of the stage. The main flow patterns associated with the rotor unsteadiness are described through a few pictures of the measured velocity components and of the Reynolds-stress distributions. Obviously, the most outstanding flow phenomena occur in the upper part of the rotor channels and take place along the stator blades suction side. In the moving row, secondary complex flow structures are highlighted, and the structure of the separated flow along the stator blade is analyzed. NomenclatureC x = axial blade chord at midspan (e b , e g , e y ) = unity vectors of the color frame of reference f −1 RTR = rotor blade passing period H = channel height h = height k = phase of a collected samplė m = mass-flow rate R tip = radius at rotor-blade tip U = peripheral velocity of the rotor blades, = · R tip V = absolute velocity V = absolute velocity vector in the cylindrical compressor frame V color = velocity vector in the color frame of reference W = relative velocity W = relative velocity vector in the cylindrical compressor frame (x, R, θ) = cylindrical system of coordinates (x is the engine axis) θ RTR = azimuthal coordinate in the cylindrical relative frame of the rotor λ = color wavelength τ xx = component of the Reynolds tensor in the axial direction τ xθ = component of the Reynolds tensor in the x, θ direction τ θθ = component of the Reynolds tensor in the tangential direction Subscripts b = relative to the blue (λ = 488 nm) color g = relative to the green (λ = 514 nm) color RTR = relative to the rotor STR = relative to the stator y = relative to the yellow-green (λ = 532 nm) color = rotor angular velocity Superscripts -= steady mean value ∼ = phase-averaged value = turbulent fluctuation

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Laser anemometer measurements in a compressor rotor flowfield at off-design conditions

Cited by 8 publications

References 7 publications

LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes

Three-Dimensional Navier-Stokes Computation of Turbomachinery Flows Using an Explicit Numerical Procedure and a Coupled k-ε Turbulence Model

Unsteady Off-Design Velocity and Reynolds Stresses in an Axial Compressor

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